Valve seat reconstruction tool



May 19, 1931. F. o. ALBERTSON I VALVE SEAT RECONSTRUCTION TOOL Filed Oct. 5, 192a Ja e/Zion fla/zmflwerfson Patented May 19, 1931 STAT FRANB 0., AIQBEETSON, F SIOUX CITY, IOWA, ASSIGNOB TO ALBEBTSON & com,

' DIG, OF SIOUX CITY, IOWA, A CORPORATION OF IOWA VALVE SEAT RECONSTRUCTION TOOL 16 stemincludi-ng common means for expanding said pilot stem laterally and centering same in a valve stem guide, and for reinforcing the same against bending.

Another object of the invention is the provision of a novel method of stiffening a supporting member of the class described, comprising the placing of said supporting memher in a state of tension by meansof an auxiliary member which is under compression, thereby increasing many times the stifiness of the relatively slender pilot stem, and providing a member which will hold a cutting or refacing tool much more accurately and firmly than any of the devices of the prior art.

Another object of the invention is the provision of a novel valve seat refacing tool assembly, which is more simple, more economical and more accurate than the tools of the prior art, and which is adapted to be applied and operated with a minimum expenditure of time and labor.

Another object is the provision of a novel pilot stem for valve refac ing tools of the class described, which is provided with a tripartite expanding end adapted to be brought into an engagement with the walls oi a valve stem guide, to center the pilot stein. accurately,

Another object is the provision of a valve grinder pil sin-er which may be accurateiv centerec in he valve stem de by means or an expan through the pilot an; thereof, said piiot stem provided an elongated cylindrical surface adaptea te engage complementary surface tact dricai body 23 of the tent he holder for accurately supporting a cutting tool in rotative relation to the valve seat.

Other objects and advantages of the invention will be apparent from the following description and from the accompanying drawings in which similar characters of reference indicate similar parts throughout the several views,

is one sheet,

Fig. 1 is an elevational view in partial cross section showing the pilot stem and tool holder in connection with a conventional valve seat and valve stem guide;

Fig. 2 is an enlarged view in partial cross section showing the pilot stem with its ex-' pansion rod; i I

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 2. 7

Referring toFig. 1,! 10 indicates a conventional internal combustion engine part, having a valve seat 11 and a valve stem guide 12 axially located relative to the valve seat 11. My valve-seat refacing tool consists essentially of a pilot stem, indicated in its entirety at'13, and a tool holder, indicated in its entirety at 14, the tool holder being adapted Referring to the drawings, of which there to support a refacing tool or reamer 15.

The tool holder 14 is preferably of the extremely simple and efi'ectivestructure shown, comprising an elongated cylindrical hardened steel member, having a non-circular upper end '16,- andan accurately machined cylindrical bore 17 in the opposite end. The upper end 16 may also be provided with a transverse aperture 18, adapted to receive a handle or rod 19 for use in actuating the cutter 15 At its lower end about the bore 17, the tool holder ld-is provided with a frusto-cenicai or tapered portion 20,, which is adapted to be received in the complementary aperture 21 of any one of a pluraiity of cutters i5 different types. he frusto conical suri 20 terminates in ashouider e The pilot member 13 con ises body 7 member indicated lfi its entirety common means tor expan'ctinag: said body member, and for placing the body member 1555 under tensile strain, comprising a second member 36 carried by the body member 13.

The body member 13 of the pilot stem comprises an accurately machined metal member preferably constructed of tool steel, having an upper elongated cylindrical portion 24, a frusto-conical portion 25 and a lower cylindrical portion 26 of reduced size. The lower cylindrical portion 26 is preferably but slightly smaller than the bore of the valve stem guide in which the pilot stem is to be used, and the cylindrical portion 26 is preferably not smooth surfaced, but is provided with a plurality of circumferentially ex tending grooves 27 of substantially rectangular cross section. The grooves 27 provlde the cylindrical portion with a plurality of sharp corners for better engagement within the valve stem guide 12. At the same time the cylindrical portion 26 is of sufficient area so that it is not readily worn away by continuous usage, and the accuracy of the pilot stem in centering the device may be maintained for a long period of time.

The cylindrical end portion 26 is preferably hollow,'being provided with an interior frusto-conical surface 28 which tapers toward the end of the pilot stem. That is, the

wall 29 increases in thickness toward the end of the pilot stem 13. For the purpose of centering the pilot stem during its construction, the extreme end may be provided with an inwardly tapering frusto-conical portion 30.,

The cylindrical portion 26 of the pilot stem 13 is preferably provided with three slots 31,

' 32 and 33 extending from the lower end for a substantial distance, axially of the pilot stem and the tripartite end of the pilot stem is adapted to be sprung apart to engage the sides of the valve stem guide 12.

In this connection it should be noted that the thickness of the walls 29 is accurately gauged so that each of thes lit ends 34 is forced out an equal distance by, the end 35 of a camming member 36, and as the pilot stem is split three ways, this results in the accurate centering of the pilot stem by means of the engagement of the three parts 34 of the pilot stem, with the valve stem guide. i

The pilot stem is also. provided with the frusto-conical portion 25 which extends from the reduced cylindrical portion 26 to the cylindrical portion 24, and the largest diameter of the frusto-conical portion 25 is preferably greater than the bore of any of the valve stem guides 12 with which the pilot stem is to be used. The frusto-conical portion 25 is thus adapted" to engage the edge of the valve stem guide 12 and the pilot'stem 13 is automaticall centered at this point.

The auxi iary stifienin and camming member 36 may consist o a. rod having a tapered frusto-conical surface 35. The frusto-conical end 35 is adapted to engage the surface 28 when the camming member 36 is moved axially in the pilot stem, forcing the split ends '34 apart.

p In order to increase the accuracy of the cen tering operation, the camming member or rod 36 may be provided with an elongated cylindrical surface 37 adapted to be slidably received-in a complementary bore 38, and the pilot stem is provided with a counter-bore 39 which is threaded as at 40 to receive the complementar y threaded portion 41 of the camming member 36.

At its opposite end the camming member 36 is provided with a noncircular head 42, the head being of less diameter than the cylindrical surface 24 and the bore 17, so that the head of the pilot stem rod 36 may be received in the bore 17.

The operation of my valve seat reconstruction tool will now be described with respect to the refacing of a valve seat, but I desire it to be understood that my tools may be used as well for cutting out the valve seats and forming recesses for the insertion of new valve seat rings, as Well as for any other operations requiring an accurate pilot stem.

The conventional valve having been removed from the seat 11 and from the valve stem guide 12, the pilot stem 13 may be inserted in'the guide 12 until the frusto-conical surface 25 prevents further movement of the pilot stem into the valve stem guide. The frusto-conical surface 25 will thereby automatically cam the pilot stem to a central position at that point relative to the valve stem guide 12, after which the pilot stem rod or tensioning member 36 may be screwed down into the pilot stem, expanding the split ends 34 into engagement with the sides of the valve stem guide 12 at the lower end of the valve stem guide 12.

As the end 35 of the camming member 36 is accurately frusto-conical, and as the thickness of the walls 29 of the pilot stem is accurately uniform, each of the split ends 34 will move outward an equal amount and the lower end of the pilot stem will also. be accurately centered in the valve stem guide 12. This accurate centering could not be accomplished so accurately with more or less split ends than three ends, because three points in the circumference of a circle accurately determine the location of the circle and hence determine the position of its center.

At the same time, the end 35 of the camming member 36 wedges the tripartite end 34 into close engagement with the walls of the valve stem guide so as to fix the pilot stem in the guide, after which further rotation when placed under tension, and as two spaced points upon the pilot stem are accurately centered in the valve stem guide, my pilot stemis peculiarly adapted to support cutters or refacing tools of any kind to rotate upon the true axis of the valve stem guide and valve seat 11, and my pilot stem does not permit any deflection of the cutters or other tools when the cutter engages relatively hard or soft parts of the seat.

As a result, it is unnecessary to use any other aligning orsupporting means than the simple pilot stem 13, unless it is desired to support the tool in fixed position, so that other operations may be performed after the valve seat is reconstructed or refaced. The pilot stem of the present invention ma of course be employed with other devices or holding the tools in proper position after they have been centered with this pilot stem.

After the body member 13 has been placed under tension it is desirable to give the head as of the pilot stem a slight tap with a light hammer to bring the frusto-conical surface 43 into firm enga ement with the walls of the valve stem gui e 12.

I am aware that pilot stems have been con structed which have expanding ends, but none of the pilot stems of the prior art has been provided with a tripartite end, nor do any of the pilot stems of the prior art include means for stifiening the pilot stem by placing its body member in a condition of stress.

The tool holder 14, with an appro riate reamer or cutter 15, may then be place upon the upper end or the pilot stem, where it is rotatably supported by the cylindrical portion 24 in the bore 17. The bore 17 is of sufiicient lengthso the cutter 15 may feed downward as required, the feed being determined by the pressure placed on the handle 19 or upon a power device connected to the non-circular end 16 of the tool holder 14.

My pilot stem may be inserted and adjusted from the seat side of the valve, and it is not necessary to turn any engine parts u side down on the bench in adjusting t e ilot stem, nor is it necessary to work from low, so that my pilot stem may be inserted and removed with a-minimum of operations.

It should also be noted that the pilot stem and tool holder each consists of integral cylindrical parts sis-distinguished from parts which are threaded together, so that these members may beaccurately machined in their manufacture, and there is no possibility of the accuracy of their shape or size being changed, as is the case where the pilot stem is made of a plurality of sections threaded together.

It will thus be observed that I have invented a pilot stem and tool holder which is adapted to more accurately center valve seat refacing tools or other cutters, so that the seat is cut accurately with reference to the axis of the valve stem. My pilot stem may be placed under astate of tension after the centerin has been accomplished, so that the relatively slender stem assumes a quality of stiffness heretofore unknown in any of the stems of the prior art.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the recise details of construction set forth, but esire to avail myself of all changes within the scope of the appended claims.

Having thus described my invention, what ll claim is new and desire to secure by Letters Patent of the United States, is:

LA pilot member for valve tools, comprising an elongated body having a bearing surface at its upper end for rotatively receiving and supportin a'valve tool holder, said body havin a s ender integral lower stem adapted toie received and fixedly secured in a valve stem guide in centered position, said body and stem having an axial bore, means for engaging the upper end of a valve stem guide, an expansion rod threaded in said bore and projecting from the upper end thereof, said rod having a camming surface atits lower end, and said stem being split at its lower end, and camming surfaces formed in said bore on the split ends of said stem to reduce the size of the end of said bore, said rod being adapted to be threaded into said bore to initially expand said split ends into engagement with a valve stem guide, and said camming surfaces finally acting as abutments on further movement of said rod into said bore, to efi'ect a substantial compression of said rod against corresponding tension in a said stem and body, to stifien said pilot and adapted tocenter the pilot in the upper for valve tools, com-J tee a s ender integral lower Y end of the guide, an expansion rod threaded in said bore and projecting from the upper end thereof, said rod having a cammin surface at its lower end, and said stem eing' 5 provided with a tripartite split end to determine the location of the lower end of the pilot in the guide, and camming surfaces formed in said bore on the split ends of said stem to reduce the size of the end ofsaid bore, said rod being adapted to be threaded into said bore to initially expand said split ends into engagement with the valve stem guide, and said camming surfaces finally acting as abutments on further movement of said rod into said bore, to place said rod under sufiicient compression against the tension of said body and stem to stiffen said pilot.

In Witness whereof, I hereunto subscribe my name this 28 day of September, 1928. FRANS o. ALBERTSON. 

